HBoundsCheck shouldn't ignore Tagged input representations unconditionally

BUG=v8:2740
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/16917003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15267 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Distinguish times_8 and times_pointer_size for X64

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/17550005

Patch from Haitao Feng <haitao.feng@intel.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@15268 ce2b1a6d-e550-0410-aec6-3dcde31c8c00